Work

Record-low-loss single-ring anti-resonant hollow-core fiber for damage-free delivery of megawatt-peak-power femtosecond pulses

Year: 2026

Type: article

Abstract: Flexible delivery of ultrafast lasers with multi-megawatt peak power is hindered by the fundamental trade-offs among loss, nonlinear damage, and beam fidelity in optical fibers. Here, we report a single-ring anti-resonant hollow-core fiber (AR-HCF) that achieves a record-low propagation loss of 1.6 dB/km at 1058 nm for its design type. The fiber exhibits near-diffraction-limited single-mode guidance with M 2 of 1.07/1.05 within the 1-μm laser band. Utilizing this platform, we demonstrate damage-free transmission of pulses with an incident peak power of 155.6 MW (70 μJ, 450 fs). A pivotal comparative study between short (60-cm) and long (15-m) fiber segments reveals that the short fiber maintains high transmission efficiency of 85.7% and stable beam quality at 70 W input. In contrast, the long fiber suffers from efficiency roll-off to about 54% and severe spectral broadening of approximately 87 nm with a characteristic redshift. The observed performance degradation in the long fiber is consistent with a contribution from air-induced nonlinearities. Our work not only establishes a new benchmark for AR-HCFs but also offers a promising platform for developing flexible, high-fidelity delivery of ultrafast lasers at the multi-megawatt level.

Source: Optics Express

DOI: 10.1364/oe.610931